dikatalisis

Dikatalisis is a form of catalysis in which two distinct catalysts cooperate to accelerate a chemical transformation. In a dikatalytic process, each catalyst can activate a different substrate or reaction step, or one catalyst can modify the reaction environment or the substrate to enable the action of the other. The two catalysts may operate within a single catalytic cycle or in parallel cycles, and the overall rate and selectivity arise from their combined action rather than from a single catalytic species. Dikatalisis is often referred to as co-catalysis, dual catalysis, or synergistic catalysis, with terminology varying among subfields.

Mechanisms commonly involve complementary activation modes. In organocatalysis and metal catalysis, one catalyst may form a reactive intermediate such as an enamine or iminium species while the other catalyst facilitates a transformation on the activated intermediate. In photoredox-assisted dual catalysis, a photocatalyst generates a radical or activated species that is then consumed by a second catalyst, typically a transition-metal catalyst, to complete the catalytic cycle. Relay catalysis is a related concept in which an intermediate generated by one catalyst is handed off to the second.

Applications are widespread in organic synthesis, particularly for enantioselective transformations, carbon–carbon and carbon–nitrogen bond formations, and complex rearrangements. The approach expands the scope of reactions achievable by a single catalyst and can enable milder conditions, higher selectivity, or new transformations.

Challenges include compatibility between catalysts, control of turnover, and optimization of cooperative effects. Ongoing research seeks to understand the factors that govern synergy and to develop general design principles for dicatalytic systems.